Various methods of manufacturing contact lenses are known, including spin casting, lathing (for example by diamond turning), and cast molding (for example, using injection molded mold halves). In particular, cast molding of contact lenses involves forming a pair of mold halves (i.e., a first mold half and a second mold half), placing a volume of a contact lens formulation on an optical quality surface of one of the two mold halves, and placing the two mold halves in contact with each other to form a contact lens mold assembly that has a contact lens-shaped cavity containing the contact lens formulation. The contact lens mold assembly is then exposed to conditions to cause the contact lens formulation to polymerize or cure in the contact lens mold assembly. As understood in the art, the mold halves may be referred to as “mold sections” (i.e., first and second mold sections) or “mold members” (i.e., first and second mold members). Using cast molding processes on automated high speed manufacturing lines, contact lenses can be manufactured in large numbers, for example, tens of thousands of lenses each day. Increases in the rate of manufacture of contact lenses can be expected to bring down the cost of each lens. It is important, however, that increased rates of manufacture do not compromise the quality of the lenses produced.
When contact lenses are formed by cast molding using injection molded contact lens mold halves, the process includes many steps. For example, the process can include closing two halves of injection molding mold tools provided in plates of an injection molding machine, forming the contact lens mold halves in the closed injection molding mold tools, opening the mold tools containing the injection molded mold halves, removing the injection molded mold halves from the opened mold tools, and optionally transferring the newly formed mold halves to a transporter for further processing. As understood by persons skilled in the art, and as used herein, an injection molding mold tool refers to the metallic inserts used to form curved surfaces of the contact lens mold halves. The metallic inserts are typically provided in plates of an injection molding machine. One or both of the metallic inserts, or mold tools, will have an optical quality surface used to form a lens-forming surface of a contact lens mold half. Each of these steps requires that the mold tools and mold halves be treated with care in order to avoid damaging them or contaminating them. In some cases, the thermoplastic material of the newly formed mold halves can still be warm and/or somewhat malleable shortly after the injection molding process has been completed. The needs of high-speed manufacturing lines require apparatus and methods for rapidly removing the newly formed injection molded mold halves from the mold tools without damaging the mold tools or the newly formed mold halves.